In the medical field, medical tubing is utilized to convey fluids to and from a patient. Tubing is also used in various other non-medical fluid transfer fields as known in the art. Tubes are bonded, in some embodiments, to a female fitting wherein the outer diameter of the tube is bonded to the inner diameter of the female fitting.
Flexible tubing made with essentially non-polar surfaces and relatively difficult to bond (co)polymers such as polypropylene, polyethylene, styrenic block copolymers and blends thereof can be difficult to bond to traditional female connectors utilizing a conventional solvent bonding technique, wherein the tubing has an end that is coated, such as by dipping, and then inserted into the female fitting.
To improve bonding between a tube and a connector, different techniques have been developed, see U.S. Pat. Nos. 8,871,864 and 8,871,317, which involve the use of adhesives, U.S. 2012/0150150 which incorporates the use of an insert liner, and U.S. Pat. No. 8,735,491 which utilizes a halogen-free, plasticizer-free thermoplastic elastomer compound reportedly capable of being solvent bonded or welded to another thermal plastic material utilizing cyclohexanone alone or with methyl ethyl ketone.
As evidenced by the various approaches taken, there is a demand for practical and cost effective ways to improve the retention force between tubing and a female fitting of a connector.